Wow Anyone seen these pictures? Could they explain dark matter?

In summary, this discovery is a new structure in the milky way and has nothing to do with dark matter.
  • #1
komodekork
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  • #2
What?! No. It has nothing to do with dark matter/energy. Did you even read the article?
 
  • #3
zhermes said:
What?! No. It has nothing to do with dark matter/energy. Did you even read the article?

Yes, I did read the article. I don't know much about dark matter, but as i understand it, the evidence for dark matter is that that the velocity curve of the galaxy falls off much slower than we expect with just the mass we see.

So this is a new, never before seen gigantic structure in the milky way, and my question is could the mass of this structure account for the flattening out of the velocity curve near the edges of the galaxy?

The article doesn't say anything eighter way, so could you expand on why this can not be? Is it as I said that the density profile is incompatable with two blobs on both sides, or is there something else I'm missing?
 
  • #4
it is mostly radiation - highly energetic electrons - it wouldn't substantially alter the total projected mass for the milky way, just like a charged battery does not weight more than a depleted one - the difference is minuscule at most

this feature is common to all galaxies, just like quasars and pulsars have jets, in fact I am surprised it took NASA so long to discover it
 
  • #5
Ah yes, the dark matter busters :D

Nevertheless I could never figure why those guys expect cosmic rays to interact with dark matter, in my book this is just wasting of resources in order to make a living on scientific funds...
 
  • #6
proteus13 said:
it is mostly radiation - highly energetic electrons - it wouldn't substantially alter the total projected mass for the milky way, just like a charged battery does not weight more than a depleted one - the difference is minuscule at most

this feature is common to all galaxies, just like quasars and pulsars have jets, in fact I am surprised it took NASA so long to discover it
I see. How dense would the radiation in the spheres need to be to account for the dark matter?
Ridiculously high? Because the radius of the spheres seems to be 12500 lightyears.
 
  • #7
komodekork said:
I see. How dense would the radiation in the spheres need to be to account for the dark matter?
Ridiculously high? Because the radius of the spheres seems to be 12500 lightyears.

I am afraid answering that question requires stepping out of the scientific mainstream - and this forum is neither a place for that, nor a place that tolerates it. Anyway, I doubt those are actual spheres as in the artist impressions of nasa, they are jets which decay, something that is visible on the actual images, the spherical form is just an approximation of that observation, in reality those should resemble two opposite cones pointing the center of the galaxy, with the actual decaying ends forming a sort of a number 8 figure, only more elongated, like the sign for infinity

FlavioBER - I am sorry but you seem to have difficulties expressing yourself in English, maybe you should make yourself some more busy with learning the language and topic of this forum before posting - so that you can post adequately
 
  • #8
komodekork said:
I see. How dense would the radiation in the spheres need to be to account for the dark matter?
Ridiculously high? Because the radius of the spheres seems to be 12500 lightyears.
The first problem is that the distributions are off: i.e. the dark matter 'halo' around the milky way is basically a sphere, with a radius a good deal larger than the size of the milky-way disk.

Remember that this radiation is just electrons and photons, so it doesn't match the 'cold' criteria of dark matter either.

But... the calculation would be very simple to do, to find out what density would be required to match the gravity of DM... and it would be extremely large. Significantly (between a factor of 100 and 1000) times more dense then baryonic matter in the milkyway
 
  • #9
Cool pic and a huge discovery... we're all going to die!
 
  • #10
komodekork said:
So this is a new, never before seen gigantic structure in the milky way, and my question is could the mass of this structure account for the flattening out of the velocity curve near the edges of the galaxy?

No. Not even close.

1) there's been no new matter that has been discovered. You just see remnant radiation from matter that was already known to be there.
2) the matter comes from the intergalactic medium. If you run the numbers you'll find that the amount of matter that you end up when you add all of this together is 100 times less than dark matter.
3) it's in the wrong place. The flatten of rotation curves indicates that the matter is out near the edge of the galaxy. More matter in near the axis of rotation isn't going to help.

This *is* interesting because it suggests that the milky way was an active galaxy until rather recently.
 
  • #11
komodekork said:
I see. How dense would the radiation in the spheres need to be to account for the dark matter?
Ridiculously high? Because the radius of the spheres seems to be 12500 lightyears.

It can't. If you dump more matter in the axis then it will cause all of the stars in the galaxy to rotate faster, but the reason we think that there is dark matter is that there is no drop off in the speed of the stars as you move away from the axis of a spiral galaxy.
 
  • #12
twofish-quant said:
This *is* interesting because it suggests that the milky way was an active galaxy until rather recently.

Active as opposed to what?! Dormant?
 
  • #13
baywax said:
Active as opposed to what?! Dormant?
Inactive.
 
  • #14
zhermes said:
Inactive.

Please give me an example of an "inactive" galaxy.
 
  • #15
The milky way. Or (off the top of my head), NGC 4321.
Only (something like) 10% of galaxies are active; I'm actually not sure about M31...
 
  • #16
zhermes said:
The milky way. Or (off the top of my head), NGC 4321.
Only (something like) 10% of galaxies are active; I'm actually not sure about M31...

What I mean is how do I distinguish between an active and an inactive galaxy? Thank you.
 
  • #17
An active galaxy, as can easily be found with a quick google search, is simply one which is much brighter than the standard galaxy. This is generally due to significant accretion at the central super-massive black-hole (e.g. AGN and blazars), but I believe there are instances where there is just an abnormally large rate of star formation taking place---not positive about that.
 
  • #18
zhermes said:
An active galaxy, as can easily be found with a quick google search, is simply one which is much brighter than the standard galaxy. This is generally due to significant accretion at the central super-massive black-hole (e.g. AGN and blazars), but I believe there are instances where there is just an abnormally large rate of star formation taking place---not positive about that.

Thank you for steering me in the general direction. Is a Quasar an inactive galaxy?
 
  • #19
baywax said:
Thank you for steering me in the general direction. Is a Quasar an inactive galaxy?

No, quasars are active.
 
  • #20
Eh, quasars are not galaxies but rather a sub-selection of AGN.
There are no inactive or dormnat galaxies.
Most galaxies are classified by type.
For example, A elliptical galaxy will be less active than a spiral one.
 
  • #21
madman143 said:
Eh, quasars are not galaxies but rather a sub-selection of AGN.
There are no inactive or dormnat galaxies.
Most galaxies are classified by type.
For example, A elliptical galaxy will be less active than a spiral one.

I agree in the technical sense this is true especially for people reading certain areas, however, most people, press and even books will refer to active and normal galaxies, the former having an active core and the others having a largely dormant core. Even MNRAS has a keyword for publication as Galaxies:Active.
 
  • #22
Yes, that is surely true.
I was just trying to clear the air as in there are no dormant or inactive galaxies asa most readers have suggested.
 

1. What is dark matter?

Dark matter is a form of matter that is thought to make up about 85% of the total matter in the universe. It does not emit or absorb light, making it invisible to telescopes. Its presence is inferred through its gravitational effects on visible matter.

2. How do these pictures potentially explain dark matter?

The pictures may provide evidence for the existence of dark matter by showing the gravitational lensing effect, where the light from distant objects is bent by the presence of a large mass, possibly indicating the presence of dark matter in that region.

3. How do scientists study dark matter?

Scientists study dark matter through various methods, including observing its gravitational effects on visible matter, studying the motion of stars and galaxies, and using particle accelerators to search for dark matter particles.

4. What are the current theories about the nature of dark matter?

There are several theories about the nature of dark matter, including the possibility that it is made up of weakly interacting massive particles (WIMPs) or axions. However, the exact nature of dark matter is still unknown and a subject of ongoing research.

5. Why is it important to study dark matter?

Studying dark matter is important because it makes up a significant portion of the universe and has a major influence on the structure and evolution of galaxies. Understanding dark matter can also help us gain a better understanding of the fundamental laws of physics and the origins of the universe.

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